Characteristics may contain none, one or more descriptors. They can be individually retrieved using the descriptor() function. The descriptors() function returns all descriptors as a list. The general purpose of a descriptor is to add contextual information to the characteristic. For example, the descriptor might provide format or range information specifying how the characteristic's value is to be interpreted.

bool QLowEnergyCharacteristic::isValid() const

An invalid characteristic object is not associated with any service (default-constructed) or the associated service is no longer valid due to a disconnect from the underlying Bluetooth Low Energy device, for example. Once the object is invalid it cannot become valid anymore.

Note: If a QLowEnergyCharacteristic instance turns invalid due to a disconnect from the underlying device, the information encapsulated by the current instance remains as it was at the time of the disconnect. Therefore it can be retrieved after the disconnect event.

Two QLowEnergyCharcteristic instances are considered to be equal if they refer to the same characteristic on the same remote Bluetooth Low Energy device or both instances have been default-constructed.

Two QLowEnergyCharacteristic instances are considered to be equal if they refer to the same characteristic on the same remote Bluetooth Low Energy device or both instances have been default-constructed.